Question

To what extent do the electronic configurations decide the stability of oxidation states in the first series of the transition elements? Illustrate your answer with examples.

Answer 1

The electronic configurations play a very crucial role in deciding the stability of oxidation states. The presence or absence of complete or half filled d orbitals in that oxidation state decides its stability. Also the ability to give away e^- decide the oxidation state which depends on the energy possessed by it and hence forth its electronic configuration, 

For example Sc shows +3 oxidation state only [M] 3d¹ 4s²⁺1, +2 very unstable due to presence of 1d e^- +3 oxidation state is stable with noble gas configuration. 

Mn : [Ar] 3d⁵ 4s² has +2, +3, +4, +5, +6, +7 states but only +2 and +7 states are stable due to the half filled d orbital or completely empty d orbital. 

similarly Ti = +2, +3, +4 with +4 most stable due to the same reason.